Reactions of Excited Organic Molecules in Vitreous Solutions

2 Reactions of Excited Organic Molecules in Vitreous Solutions 

The other pioneering work on electron tunneling in reaction of excited particles dealt with the photoionization of organic molecules in vitreous matrices [38]. The studies made in this work were based on the following idea. 

Owing to a relatively high (compared with molecules in the ground electronic state) probability of electron tunneling for excited molecues, this process, at sufficiently short distances between the excited molecules and the particles of electron acceptors, can compete with the ordinary over-barrier electron transfer 

The transition from the two-quantum to the one-quantum mechanism was indeed discovered [38] in studying the reactions of ionizing naphthalene (Nh) and diphenylamine (DPA) in the presence of CCl4 in vitreous alcohol (CH3OH) matrices at 77 K 

The decay kinetics of excited electron donor molecules (the intensity of fluorescence is proportional to the concentration of excited molecules at any given time) can be interpreted in two ways. First, one may try to approximate it with the sum of two exponents, one of which refers to the decay of the fluorescence of free donor molecules and the other to that of the complex between the donor and the acceptor. This interpretation is similar to the description of the two-exponential decay of the fluorescence observed in the presence of two compounds containing heavy atoms [40] 

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